The invention relates to elastomeric damping elements for controlling and minimizing the harmful effects of shock and vibration on electronic and other equipment and components.
Elastomeric materials are employed extensively in applications were shock and vibration must be minimized. Such applications include sports equipment, tools, automobiles, airplanes, electronic equipment and components and many other types of apparatus. It is also becoming increasingly important to minimize failures due to impact forces applied to electronic equipment, such as digital computers, specially when such equipment is employed in harsh, rugged environments.
Previously, various elastomeric materials has been used or suggested for use to provide shock and/or vibration damping, as stated in U.S. Pat. No. 5,766,720 issued Jun. 16, 1998 to Yamagishi. These materials include natural rubbers and synthetic resins, such as polyvinylchlorides, polyurethane, polyamides, polystyrenes, copolymerized polyvinyl chlorides, and polyolefine synthetic rubbers, as well as synthetic materials such urethane, EPDM, styrene-butadine rubbers, nitrites, isoprene, chloroprenes, polylene, and silicones.
The elastomeric elements employed in the prior art were commonly formed into typical geometric shapes, such as spheres, squares, right circular cylinders, cones, rectangular, and the like, as illustrated in U.S. Pat. No. 5,776,720. These typical geometric shapes, however, did not satisfactorily eliminate the transfer of compressive forces through the damping device, and thus, did not minimize, or eliminate shock and vibration to the degree accomplished by the devices of the present invention.
In a pending U.S. patent application, Ser. No. 09/495,693 entitled xe2x80x9cElastomeric Damping Elements and Applications for Reducing Shock and Vibration,xe2x80x9d elastomeric damping elements of block shapes were disclosed. These elastomeric damping elements were formed to have an elongated parallelogram cross-sectional shape with a first flat mounting surface that extended parallel to a second flat mounting surface where the parallelogram cross-section of the element and was constructed so that a line drawn normal to one of the flat mounting surfaces would not intercept the other of the flat mounting surfaces. As an option, a space in the interior of the element could be provided, which is filled with particulate or fluid matter that may be contained in a deformable package. Materials that have a different damping characteristic than the elastomeric device itself, may be poured in fluid form into the interior of the element where they solidify.
Pending U.S. patent application Ser. No. 09/770,474 entitled xe2x80x9cElastomeric Damping Sheets,xe2x80x9d discloses elastomeric sheet material that was formed of a continuous, flat elastomeric sheet or layer that has the plurality of channels that run through it, or at least partly through it. The remaining material was formed with a plurality of structures that when viewed alone, a cross-sectional cutting line formed a number of interconnected elastomeric damping elements each of which had a generally parallelogram cross-sectional shape.
A structure for dissipating forces applied to it includes a number of stacked elastomeric sheets which are formed with identical holes that have a periphery that is symmetrical around its centers. The sheets are stacked so that the passageways of continuous elastomeric material are formed through said structure. When the sheets are stacked, the passageways are aligned in such a way that center lines through the centers of holes in different levels of the stack of sheets form parallel lines that pass on opposite sides of continuous elastomer material paths at least one of which extends from one external support surface to a parallel support surface on the opposite side of the stack of sheets, this allows for dissipation of shock through sheer forces when a compressive force is applied normal to the support surfaces. An elastomeric material of a different composition than the elastomer material of the sheets, may be filled into the holes of the stack when the stack construction is completed.